Automatic telephone-exchange system



June 22 1926.

O. R. MILLER AUTOMATIC TELEPHONE EXCHANGE SYSTEM Filed 001;. 6. 1923 w m M \N L w A 5 I ll w k w 1 A W W w I Q AEEAWZMMLB ANN \N J$=E z Em A W UH L Y s m Q N m Patented June 22, 1926.

UNITED STATES PATENT OFFICE.

OHHEB B. KILLER,

COMPANY, INCORPORATED, YORK.

01' BROOKLYN, NEW YORK, ASSIGNOB '10 WESTERN ELECTRIC 01' NEW YORK, N. Y., A. CORPORATION 01' NEW AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

Application filed October 6, 1828. Serial K0. 688,922.

This invention relates to impulse repeaters, and more particularly to impulse repeaters for automatic telephone systems.

The object of this invention is to insure the proper operation of automatic switching apparatus during selection.

In accordance with this invention the impulses produced by the calling device operate an impulse relay which controls a chain of relays including an impulse repeating relay, and the irregular impulses received by the impulse relay are reproduced by the relay chain in such a manner that the impulses supplied to operate the automatic switching apparatus are of substantially uniform duration.

The invention is diagrammatically shown in the drawing, comprising but a single sheet, wherein 1 represents a calling station, R, represents the repeater circuit connected to a selector S. S is one of a group of second selectors to which the selector S has access, G represents a connector, and 23 the called station. The selectors S and S and connector C may be of the type used and fully described in U. S. Patent to H. P. Clausen No. 1,271,133, dated July 2, 1918.

The invention will be most readily understood from a detailed description of the operation.

It should be understood that a line switch or line finder or other suitable linking circuit may be introduced between the station 1 and the repeater R, and that a trunk finder may very readily be used to connect the repeater R with the selector S without in any way departing from the spirit of this invention. I

When the receiver is removed at the calling station 1, a circuit to operate impulse relay IR, is closed as follows; battery, rela IR, 40, 4, 1, 2, 5, 41, relay IR to groun Relay IR closes an obvious circuit to operate relays 7 and 8 in series and a second obvious circuit to charge the condenser 9.

Relay 8 closes an obvious circuit to operate relay 10, which now locks under control of relay 11, and closes an obvious circuit to operate relay 12. Relay 10 closes a bridge by way of the left winding of relay 13, both windings retard coil 14, and the leads 15 and 16 to the windings of impulse relay 17 which now operates and closes an obvious circuit to operate relay 18. Relay 13 does not operate due to the high resistance 1n series with it. While a circuit is closed through the rightwinding of rela 13 upon the operation of relay 18, this winding opposes the left winding. The circuit is now ready to receive the first series of impulses set up by the dial 2 at the calling stat1on 1. The dial 2 is now operated, and released and as it returns to normal the circuit through the loop formed by the calling station 1 is opened by the impulse springs not shown of the dial 2, thus releasing the IR relay. The IR relay in releasing opens the circuit through relays 7 and 8, releasing relay 7, thus disconnecting the condensers 32 and 33 from the impulse circuit and short circuiting the left windings of relay 13 and the retard coil 14 to reduce the resistance of the trunk bridge. Relay 8, which is slow to release, remains operated throughout the impulse period, but relay 7 which is quick to release but slow to operate does not reoperate until the end of the impulse train.

When the IR relay releases a circuit is also closed to discharge the condenser 9 in series with the winding of relay 11. Relay 11 operates during this momentary discharge of the condenser 9, and opens the holding circuit for relay 10 which releases, thus opening at 19 the bridge through relay 17 which releases. Relay 10 in releasing also releases relay 12, thus closing the circuit to reoperate relay 10, and close at 19 the bridge to reoperate relay 17. The open period of the impulse repeated to relay 17 will therefore be the time which elapses between the o ening of contacts 19 and 20, the release 0 relay 12, and the reclosing of 19 and 20 by the reoperation of relay 10. As the relays operate in local circuits, the only important factor tending to vary this open period is the change in voltage, and it is evident that by holding the voltage within close limits the open period may be made almost a constant. Hence so long as the IR relay responds to the impulses ,produced by the dial 2 and closes its front'g contact long enough .to charge the condenser 9 and its back contact long enough to operate the relay 11 the cycleof operations of relays 10, 12 and 17 will take place irrespective of the ratio between the open and closed periods of the im ulse produced by the dial 2.

Each time relay 1O releases a ground is supplied at 21 which serves to keep relay 8 operated and to short-circuit relay 7. By this means the proper operation of relays 7 and 8 is made more certain, as they do not depend solely upon the operation of the IR relay. V

The impulses produced by the dial 2 are thus repeated by the operation and release of relay 10 to .the impulse relay 17 of the selector S which follows the impulses and causes the selector S to function in the manner described in said patent. The selector S hunts for an idle trunk as described in said patent and the connection is extended by the operation of relay 22 to the selector S where the selective operation is repeated in substantially the same manner, as in the selector S as described in said patent. The connection is extended to the connector C thence to the called line which is signalled in the manner described in said patent. When the called line answers the direction of the current is reversed at the connector C as shown in said -patent and relay 13 now operates closing a circuit to operate relay 24 as follows, battery, relay 24, 25, 2e, 27, 2s, 29, 30, to ground at the connector. Relay 24 locks in parallel with the right winding of relay, 13, over the circuit previously traced and completes the connection between stations 1 and 23. Relay 24 also opens the circuit through the IR relay which releases, re-

, leasing relays 7, 8, 10 and 12. The release of relay 10 opens at 19 and 20, the circuit through the left winding of'relay 13. Relay 13 may or may not release at this time depending upon whether or not the current flow through its right winding is suflicient to hold the relay in the operated position.

During conversation ground for holding relays 24, 22 and 39 is supplied by the connector C under'control of certain relays not shown but described in said patent.

When the calling station 1 disconnects the ground at 31 is removed and relays 22, 24 and 39 release. The release of relay 24 restores the repeater R to normal. When relay 22 releases, the selector S is restored to normal as described in said patent. The

release of relay 39 restores the line 23 to normal.

--The resistances 4 and 5 are used for prorelay 11. The resistance 36 is used" to slow up the'release of the relay 12. The resistance '37 and condenser 38 are used to increase the range of the impulse relay 17.

' e for purposes of illustration the re peater circuit is shown in the drawings as a in a train of automatic switches in a is not so limited 'but may be used in an signalling system Where impulse signals is desired.

The invention claimed is:

1. In a signaling system, the combination of an electro-responsive device, a condenser, a circuit, an electro-responsiv'e device'in said circuit for charging and discharging said condenser thereby momentarily operating the repeating of said first mentionedelectro-responsive device, an impulse circuit and a chain of inter dependent electro-responsive devices one of which is controlled by said first mentioned electro-responsive device to control said impulse circuit, and electro-responsive means responsive to the impulses produced in said impulse circuit.

2. In an automatic telephone system, the combination of a relay and a condenserfa second relay for charging and discharging said condenser thereby momentarily operating said first mentioned relay, means for intermittently operating said second relay, an impulse circuit, a chain relays including the relay controlled by said first mentioned relay for controlling said impulse circuit, and electro-responsive means responsive to the impulses produced in said impulse circuit.

3. In a signaling system, a chain of interdependent relays, a device for repeating impulses comprising an impulse sending relay forming one of said chain of interdependent relays, an electro-responsive device controlling said chain of relays, a condenser, and a second electro-responsive device provided with means for operating said first electroresponsive device through the medium of said condenser.

4. In an automatic telephone system, a chain of interdependent relays, a device for repeating impulses comprising an impulse sending relay forming one of said chain of interdependent relays, a second relay controlling said chain of relays, a condenser, and a third relay provided with means for operating said second relay through the:

step-by-step telephone exchange system it of interdependent I sending relay forming one of said pair of interdependent relays, a second relay con trolling said pair of relays, a condenser, and a third relay provided with means for operating said second relay through the medium of said condenser.

6. In a signaling system, a chain of mterdependent relays, a device for repeating impulses comprising an impulse sendlng relay forming one of said chain of interdependent relays, a second relay controlling said chain'of relays, a condenser, a third relay provided with means for 0 eratin sa d second relay through the me ium 0 said condenser, a slow relay primarily controlled by said third relay, and secondary means for controlling said slow relay independent of said third relay.

7. In an automatic telephone system, a pair of interdependent relays, a device for repeating-impulses comprising an impulse sending relay forming one of said pair of interdependent relays, a second relay controlling said pair of relays, a condenser, a third relay provided with means for operating said second relay through the medium of said condenser, a slow relay primarily controlled by said third relay, and means controlled by said pair of relays for controlling said slow relay independently of said third relay.

8. A device for transforming distorted impulses into impulses of substantial uniformity comprising an impulser, a condenser, an electroresponsive device controlled by the impulser through the medium of the condenser, an impulse circuit, and a group of mutually controlled electroresponsive devices having a cycle of operations which cycle is always repeated in a substantially uniform interval of time, the cycle which includes the opening and closing of said impulse circuit being initiated by the momentary operation of said condenser controlled electroresponsive device.

9. A device for transforming distorted impulses into impulses of substantial uniformity comprising an impulse sender, an electroresponsive device controlled thereby, a condenser, a relay controlled by the electroresponsive device through the medium of the condenser, an impulse circuit, and a group of mutually controlled electroresponsive devices having a cycle of operations, which cycle is always repeated in a substantially uniform interval of time, the cycle which includes the opening and closing of said impulse circuit being initiated by the momentary operation of said relay.

10. A device for transforming distorted impulses into impulses of substantial uniformity comprising an impulse sender, an impulse relay controlled thereby, a condenser charged when the forward contact of said impulse relay is closed and discharged when the back contact of said relay is closed, a relay responsive to the dischar e of said condenser, an impulse circuit, an a group of mutually controlled electroresponsive devices having a cycle of operations, which cycle is always repeated in a substantiall uniform interval of time, the cycle whici includes the opening and closing of said impulse circuit being initiated by the momentary operation of said condenser controlled relay.

11. A device for transforming distorted impulses into impulses of substantial uniformity, comprising an impulse sender, an impulse relay controlled thereby, a condenser charged when the forward contact of said impulse relay is closed and discharged when its back contact is closed, a relay responsive to the discharge of said condenser, an impulse circuit, and a plurality of mutually controlled relays having a cycle of operations, which cycle is always repeated in a substantial uniform interval of time, the cycle which includes the opening and closing of said impulse circuit being initiated by the momentary operation of said condenser controlled relay.

12. A device for transforming distorted impulses into impulses of substantial uniformity, comprising an impulse sender, an impulse relay controlled thereby, a condenser charged when one contact of said impulse relay is closed and discharged when its alternate contact is closed, a relay con trolled by said condenser in discharging, an impulse circuit, and a plurality of mutually controlled relays having a cycle of operations, the cycle which includes the opening and closing of said impulse circuit always being repeated in a substantially uniform interval of time, the operation of the mutually controlled relays being controlled exclusively by the condenser controlled relay.

13. A device for converting distorted impulses into impulses of substantially uniform characteristics comprising an electro-responsive device responsive to distorted impulses, acondenser charged and discharged under control thereof, a relay responsive to said condenser in discharging, an impulse producing circuit, and a plurality of mutually con trolled relays havinga cycle of operations initiated under control of the condenser responsive relay, each step in the cycle being repeated in a substantially uniform interval of time, one step in each cycle being the production of an impulse in the impulse producing circuit.

14. A device for converting distorted impulses into substantially uniform impulses comprising an electro-responsive device responsive to distorted impulses, a condenser charged and discharged under control thereof, a relay responsive to said condenser in ly uniform interval of time, one step comdischargin a circuit for producing imprising the opening and another the closing pulses, an a plurality of mutually con of the impulse producing circuit.

trolled relays having a cycle of operations In witness whereof, I'hereunto subscribe 5 initiated under the exclusive control of the my name ths 27th day of September A.

condenser responsive relay, each step in the D., 1923.

cycle always being repeated in a substantial- OIIMER R. MILLER. 

